1. Field of the Invention
This invention relates to a method of drying which is especially effective for forming solid, particulate and stable products from carbohydrate solutions, including complex carbohydrate solutions.
2. Description of the Prior Art
U.S. Pat. Nos. 3,600,222, 3,956,009 and 4,162,926 teach methods for forming particulate, free-flowing solid products from sugar solutions.
U.S. Pat. No. 3,600,222 discloses a process for drying sucrose solutions wherein separate feeds of sucrose solution and fine sucrose particles are dispersed in a current of heated air, water is evaporated from the sucrose solution which becomes coated on the sucrose particles, and the coated particles are recovered.
U.S. Pat. No. 3,956,009 teaches a process for preparing dried free-flowing particulate solid particles from fructose solutions wherein a dispersed fructose solution is dried in a current of heated gas in the presence of separately introduced recycled dried solid product.
U.S. Pat. No. 4,162,926 is directed to a process for the production of a dried, free-flowing stable particular sugar product from difficultly crystallizable complex sugar solutions by a process wherein dispersed complex sugar solutions are spray-dried in a current of heated gas in the presence of separately introduced recycled solid product which has been subjected to a conditioning step wherein the moisture content of the spray-dried product is reduced to an amount not greater than 0.5% by contacting spray-dried product with a conditioning gas having a humidity of less than 50% and a temperature below the melting point of the solid.
While the prior art has provided means for drying sugar solutions, including complex sugar solutions, improvements are desirable, especially in the specific means used to obtain the low water content necessary for product particles having free-flowing stability. Previously known processes depend upon convectively and conductively supplied energy to provide heat of water evaporation. The allowable temperature differences between the heat supplying source and the solid surface at which evaporation occurs are economically and process operationally important. These facts impose severe and costly equipment design requirements for commercial operation of previously knowm methods of producing dried, solid, particulate sugar products from complex sugar solutions.